The development of efficient heterogeneous Fenton catalysts is mainly by "trial-and-error" concept and the factor determining HO activation remains elusive. In this work, we demonstrate that suitable facet exposure to elongate O-O bond in HO is the key parameter determining the Fenton catalyst's activity. CuFeO nanocubes and nanoplates with different surface facets of {110} and {012} are used to compare the effect of exposed facets on Fenton activity. The results indicate that ofloxacin (OFX) degradation rate by CuFeO {012} is four times faster than that of CuFeO {110} (0.0408 vs 0.0101 min). In CuFeO {012}-HO system, OFX is completely removed at a pH range 3.2-10.1. The experimental results and theoretical simulations show that OH is preferentially formed from the reduction of absorbed HO by electron from CuFeO {012} due to suitable elongation of O-O (1.472 Å) bond length in HO. By contrast, the O-O bond length is elongated from 1.468 to 3.290 Å by CuFeO {110} facet, HO tends to be dissociated into -OH group and passivates {110} facet. Besides, the new formed ≡Fe* on CuFeO {012} facet can accelerate the redox cycle of Cu and Fe species, leading to excellent long-term stability of CuFeO nanoplates.

Two-dimensional (2D) materials have attracted great attention by researchers due to their fascinating properties and promising applications. However, the synthesis methods for few layers are usually difficult to expand to large area applications because of their low yield. In this paper, graphene-like MoSe2 nanosheets are successfully and scaleable synthesized by a facile and low-cost hydrothermal method under the synergy of PVP and graphene. The ultrathin MoSe2 nanosheets are typically 1–3 layers, which are confirmed by HRTEM. This unique structure makes this MoSe2 electrode material show superior activity toward the electrocatalytic hydrogen production with a low Tafel slope about 70 mV·dec–1. Furthermore, the synthesized graphene-like MoSe2 nanosheets had a high stability during the electrocatalytic process and we nearly cannot find the degradation after 1000 cyclic voltammetric sweeps.

Fabricating a cost effective hydrogen evolution reaction catalyst without using precious metal elements is in crucial demand for environmentally-benign energy production. In this work, the thin and edge-rich molybdenum disulfide nanosheets, with carbon doped in the interlayers and decorated on graphene, were developed by a facile solvothermal process. The as-synthesized nanohybrids exhibited high catalytic ability for the hydrogen evolution electrochemical reaction with an onset overpotential of 0.165 mV and a Tafel slope of 46 mV dec(-1). Furthermore, the prepared nanohybrids also showed better durability and stability. Our work may lead to a potential method for in situ production of metal carbide-sulphur hybrid nanomaterials with promising applications for the hydrogen evolution reaction.

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Advanced oxidation processes as a green technology have been adopted by combining the semiconductor catalyst MoSe2 with H2O2 under visible radiation. And novel three-dimensional self-assembled molybdenum diselenide (MoSe2) hierarchical microspheres from nanosheets were produced by using organic, selenium cyanoacetic acid sodium (NCSeCH2COONa) as the source of Se. The obtained products possess good crystallinity and present hierarchical structures with the average diameter of 1 μm. The band gap of MoSe2 microspheres is 1.68 eV and they present excellent photocatalytic activity under visible light irradiation in the MoSe2-H2O2 system. This effective photocatalytic mechanism was investigated in this study and can be attributed to visible-light-driven advanced oxidation processes.